The company traces its roots to the electronics revolution that immediately followed World War II. The company’s founders C. Howard Vollum and Melvin J. "Jack" Murdock invented the world’s first triggered oscilloscope in 1946, a significant technological breakthrough. Tektronix was incorporated in 1946 with its headquarters at SE Foster Road and SE 59th Avenue in Portland, Oregon. In 1947 there were 12 employees, and 250 in 1951. By 1950 the company began building a manufacturing facility in Washington County, Oregon, at Barnes Road and the Sunset Highway, and expanded the facility by 1956 to 80,000 square feet (7,000 m2). The company then moved its headquarters to this site, following an employee vote.
In 1956, a large piece of property in nearby Beaverton became available, and the company’s employee retirement trust purchased the land and leased it back to the company. Construction began in 1957 and on May 1, 1959 Tektronix moved into its new Beaverton headquarters campus, on a 313-acre (1.27 km2) site which came to be called the Tektronix Industrial Park. The company's IPO, when it publicly sold its first shares of stock, was on September 11, 1963. In 1974, the company acquired 256 acres (1.0 km2) in Wilsonville, Oregon where it built a facility for its imaging group. By 1976, the company employed nearly 10,000, and was the state’s largest employer. Tektronix's 1956 expansion and, in 1962, Electro Scientific Industries' similar move to Washington County and expansion are credited with fostering the development of a large high-tech industry in Washington County, a number of firms which collectively are often referred to as the "Silicon Forest".
For many years, Tektronix was the major electronics manufacturer in Oregon, and in 1981, its U.S. payroll peaked at over 24,000 employees. Tektronix also had operations in Europe, South America and Asia. European factories were located in Saint Peter's, Guernsey (then in the European Free Trade Association) until 1990, Hoddesdon (North London, UK) and Heerenveen, Netherlands (then in the European Common Market).
For many years, Tektronix operated in Japan as Sony-Tektronix, a 50-50 joint venture of Sony Corporation and Tektronix, Inc; this was due to Japanese trade restrictions at the time. Since then, Tektronix has bought out Sony's share and is now the sole owner of the Japanese operation.
Some former Tektronix employees left to create other successful "Silicon Forest" companies. Spin-offs include Mentor Graphics, Planar Systems, Floating Point Systems, Cascade Microtech, Merix Corporation, Anthro Corporation and Northwest Instrument Systems (NWIS) - later renamed to MicroCase. Even some of the spin-offs have created spin-offs, such as InFocus.